Keeper of Greed [bug]?

[Solid Rock]

Are you not suppose to get his card that forces him to skip a turn in your hand? I started a fight with him and his first attack is 150x3 damage and his card ended up in my draw pile with no way of retrieving it. Instant loss with no way to handle it seems a bit cheap.

[vert]

Rare RNG. In fact you can survive if you have 3 Evasion or some Invulnerability or some armour of resurrection. But Keeper can give you a card for instant killing him every turn - RNG again)

[Solid Rock]

Well this has happened on several runs now.

[ShinryuEXE]

Not a bug, that card gets added to your deck. It's RNG when you draw it (and the thinner your deck/the better your card draw, the more reliably you'll draw into it)
As for the 150x3 damage: If you read the tooltip of the attack, it only does that much damage because it scales relative to your current gold. So, spend more gold before you get to that fight and it'll do a lot less damage.
Or, save a Mandrake Root for the fight. Or the stun potion. Or build up Evasion. Or use cards that stun. Or apply weakness to him to halve his damage. Etc.